Air pollution control device

Abstract

An air pollution control device for controlling the velocity of discharge from an industrial chimney or smokestack in order to optimize the plume rise and thereby minimize air pollution comprising a variable pitch truncated cone adapted to be mounted at or near the top of the chimney or stack, said cone being constructed to be expandable and contractible with respect to the axis of the chimney or associated flue or flues and kinematic means manually or automatically operable to control the size of the flow path of the gases through the truncated cone.

We claim: 
     
       1. The combination with a smokestack of means at the top of the stack defining a truncated conical chamber adapted to be expanded and contracted to vary the size of the discharge opening and electrically operable kinematic means effecting the expansion and contraction of said first means to obtain control of the gas exit velocity, thereby effecting maximum plume rise from the top of the chimney. 
     
     
       2. The combination according to claim 1 wherein the base diameter of the truncated conical chamber corresponds substantially in diameter to the diameter of the inside of the chimney flue. 
     
     
       3. The combination according to claim 1 wherein the axial length of the truncated conical chamber corresponds substantially in length to 1 to 11/2 times the inside diameter of the chimney flue. 
     
     
       4. The combination with a smokestack of means at the top of the stack defining a truncated conical chamber, said means comprising a plurality of relatively long, narrow blades disposed in a circle about the axis of the stack for pivotal movement about their lower ends radially inwardly and outwardly relative to the axis of the stack and means for effecting expansion and contraction of said first means to obtain control of the gas exit velocity, thereby effecting maximum plume rise from the top of the chimney and wherein the longitudinal edges of the blades overlap. 
     
     
       5. The combination according to claim 4 wherein the means for effecting expansion and contraction is manually operable kinematic means. 
     
     
       6. The combination according to claim 4 wherein the means for effecting expansion and contraction is hydraulically operable kinematic means. 
     
     
       7. The combination according to claim 4 wherein expansion and contraction by said means for effecting expansion and contraction is determined by flow-sensitive means situated in the flow path. 
     
     
       8. The combination according to claim 4 wherein expansion and contraction by said means for effecting expansion and contraction is automatically determined by temperature pressure sensitive means situated in the flow path. 
     
     
       9. Apparatus according to claim 8 wherein the temperature pressure-sensitive means is mounted in the chimney in the unobstructed flow path of the gases and means operable by the response of said temperature pressure-sensitive means to changes in gas flow to effect operation of said second-named means. 
     
     
       10. Apparatus according to claim 4 comprising a cylindrical shell adapted to be mounted to the top of the chimney within which said relatively long, narrow blades are mounted. 
     
     
       11. The combination according to claim 4 comprising velocity sensing means for controlling operation of the means for effecting expansion and contraction of said first means in accordance with rate of emission so as to maintain a predetermined discharge rate at the top of the stack. 
     
     
       12. Apparatus according to claim 11 wherein the velocity-sensitive means comprises temperature pressure sensing means responsive to the flow path of the gases. 
     
     
       13. The combination with a smokestack of means at the top of the stack defining a truncated conical member adapted to be expanded and contracted to vary the size of the discharge opening, said means comprising a plurality of relatively long, narrow blades disposed in a circle about the axis of the stack for pivotal movement about their lower ends radially inwardly and outwardly relative to the axis of the stack and wherein the blades are arranged in inner and outer circles in overlapping relation such that movement of the blades of the outer circle inwardly effect a corresponding inward movement of the inner blades and movement of the inner blades outwardly effect a corresponding movement of the outer blades outwardly, and means for effecting expansion and contraction of said blades to obtain control of the gas exit velocity, thereby effecting maximum plume rise from the top of the chimney. 
     
     
       14. The combination with a smoke stack of means at the top of the stack defining a truncated conical chamber adapted to be expanded and contracted to vary the size of the discharge opening, said means comprising a plurality of relatively long, narrow blades disposed in a circle about the axis of the stack for pivotal movement about their lower ends radially inwardly and outwardly relative to the axis of the stack, said blades being arranged in inner and outer circles in overlapping relation such that movement of the blades of the outer circle inwardly effect a corresponding inward movement of the inner blades and movement of the inner blades outwardly effect a corresponding movement of the outer blades outwardly, spring means biasing the outer blades inwardly and means for effecting outward movement of the inner blades comprising cables connected at one end to the inner blades and to a winch at their outer ends and means for effecting rotation of the winch. 
     
     
       15. Apparatus according to claim 14 wherein a crank is provided for effecting rotation of the winch. 
     
     
       16. Apparatus according to claim 14 wherein a motor is provided for effecting rotation of the winch. 
     
     
       17. Apparatus according to claim 14 wherein the means for effecting outward movement of the blades comprises rods connected at one end to the inner blades, meshing worms and wheels at the outer ends of the rods and means for effecting rotation of the worm wheels. 
     
     
       18. The combination with a smoke stack of means at the top of the stack defining a truncated conical chamber adapted to be expanded and contracted to vary the size of the discharge opening, said means comprising a plurality of relatively long, narrow blades disposed in a circle about the axis of the stack for pivotal movement about their lower end radially inwardly and outwardly relative to the axis of the stack, said blades being arranged in inner and outer circles in overlapping relation such that movement of the blades of the outer circle inwardly effect a corresponding inward movement of the inner blades and movement of the inner blades outwardly effect a corresponding movement of the outer blades outwardly, spring means for spring biasing the outer blades inwardly and power-driven means including cords for effecting outward movement of the inner blades. 
     
     
       19. A velocity control module adapted to be mounted to the top of a chimney comprising a shell structure having an inside diameter greater than that of the chimney flue diameter, means mounted in the shell radially outwardly of the chimney flue defining a truncated conical chamber designed to be expanded and contracted to form an axially extending truncated conical flow path which may be varied in size, electrically operable kinematic means for effecting expansion and contraction of said means defining the truncated conical flow path and means operable to effect operation of the last means to maintain the velocity of discharge at a predetermined level. 
     
     
       20. A velocity control unit adapted to be mounted to the top of a chimney comprising a truncated variable pitch cone defining a conical flow path at the top of the chimney, the base diameter of which corresponds substantially to the diameter of the chimney flue so located as to be in axial alignment with the axis of the flue, said truncated cone being designed to be contracted and expanded to vary the size of the flow path, electrically operable kinematic means for effecting expansion and contraction of said truncated cone, and means operable to effect operation of said last-named means to obtain the velocity of discharge at a predetermined level.